#43 LAS Classification 2 by Vendor should sometimes be 0 (zero) after MCC

[Linda Tedrow]

The current MCC-LiDAR program does not modify point classification values of 2 (two). However, there may be instances where the application of the splining algorithim would indicate that a point with a classification of 2(two) should not necessarily be so. The 2 classification indicates that this point represents the surface or a ground location. If the mcc algorithm would not interpret this point as a ground location, the program should assign a 1 (one) value to this point.

Further, if the previous value is a zero; if the mcc-lidar program does not classify this point as a ground point is should also be assigned a 1 (one) value indicating that it is has been considered but not classified as a ground point and is still unclassified.

see http://www.asprs.org/a/society/committees/standards/asprs_las_format_v20.pdf
page 14
LAS Specification Version 2.0 PROPOSAL May 1, 2007

[Jimm Domingo]

• owner set to jimm_domingo
• status changed from new to accepted

In the LAS 2.0 proposal, at the bottom of pages 14-15, footnote 3 contains an example of classification value 1:

We extend the idea of classification value 1 to include cases in which data
have been subjected to a classification algorithm but emerged in an undefined
state. For example, data with class 0 is sent through an algorithm to detect
man-made structures â€" points that emerge without having been assigned as
belonging to structures could be remapped from class 0 to class 1.

Analogously, MCC-LIDAR detects ground points, so those points that it does not classify as ground (i.e., non-ground) should be assigned class 1. Although the program has determined that these points are non-ground, there are only partially classified because there is no single general class for vegetation. Instead, there are three classification values for vegetation based on height (low = 3, medium = 4, high = 5).

[Jimm Domingo]

• status changed from accepted to closed
• resolution set to fixed
• milestone set to 1.0 (rc4)

Fixed in revision r173.